Area Forecast Discussion
Issued by NWS Gaylord, MI

Home | Current Version | Previous Version | Graphics & Text | Print | Product List | Glossary Off
Versions: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50

000
FXUS63 KAPX 181056
AFDAPX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GAYLORD MI
656 AM EDT MON AUG 18 2014

.SYNOPSIS...
ISSUED AT 352 AM EDT MON AUG 18 2014

HIGH PRESSURE WILL REMAIN IN CONTROL OF OUR WEATHER THROUGH THE
AFTERNOON TODAY...PROVIDING SEASONABLE CONDITIONS ALONG WITH PERIODS
OF CLOUDS. RAIN CHANCES WILL INCREASE THIS EVENING AND TONIGHT...AND
CONTINUE INTO MIDWEEK...AS SLOW MOVING LOW PRESSURE MEANDERS ACROSS
THE REGION. THIS SYSTEM WILL BRING THE POTENTIAL FOR LOCALIZED HEAVY
RAINFALL OVER MUCH OF NORTHERN MICHIGAN...ESPECIALLY TUESDAY AND
TUESDAY NIGHT.

&&

.SHORT TERM...(TODAY THROUGH TONIGHT)
ISSUED AT 352 AM EDT MON AUG 18 2014

...STEADILY INCREASING CHANCES FOR RAIN...

IMPACTS: MINIMAL/NONE. AREAS OF DENSE FOG THIS MORNING. POOR
VISIBILITY.

CURRENT WEATHER AND SYNOPTIC PATTERN:

MINOR MID LEVEL RIDGING OVERHEAD WITH A WEAK SHORTWAVE TRYING TO
MAKE INROADS TO NRN MICHIGAN. THIS SHORTWAVE WAS EJECTED ENERGY FROM
LARGER SCALE TROUGH DROPPING SW FROM MANITOBA. THIS WAVE CAN`T EVEN
PRODUCE MID AND UPPER CLOUD AS THINGS ARE QUITE DRY ABOVE 850MB PER
THE 00Z APX SOUNDING. IN THE BL THOUGH...THINGS ARE MORE MOIST AND
ALSO CAPPED OFF BY A RATHER PRONOUNCED INVERSION. ADD IN WEAK LOW
LEVEL WINDS WITHIN SFC HIGH PRESSURE AXIS...AND STRONG RADIATIONAL
COOLING HAS RESULTED IN THE FORMATION OF STRATUS AND FOG. MANY AREAS
OF POOR VISIBILITY WERE COMMON IN THE HIGHER TERRAIN OF INTERIOR NRN
LOWER. FURTHER UPSTREAM...DEEPER MOISTURE (1.5"-2.0" PWATS) RESIDED
ACROSS WISCONSIN/MN AND THE DAKOTAS. THE MAIN TROUGH WITH BROAD AND
FAIRLY WEAK LARGE SCALE ASCENT WAS ABLE TO PRODUCE AREAS OF SHOWERS
AND STORMS...SOME OF WHICH HAVE PRODUCED IMPRESSIVE RAINFALL
AMOUNTS. THIS NOT DUE TO JUST THE HIGH LIQUID WATER CONTENT...BUT
ALSO TO WEAK WIND FIELDS RESULTING IN SLOW MOVING STORMS.

SYNOPTIC PATTERN/WEATHER EVOLUTION:

SFC HIGH PRESSURE WILL EXIT EAST...AND THE SHORTWAVE TROUGH FROM
MANITOBA WILL SLOWLY WORK ITS WAY INTO THE WESTERN GREAT LAKES.
INITIALLY...THE STRATUS AND FOG WILL BE PRETTY COMMON...ESPECIALLY
IN THE MORE MOIST BL OF NRN LOWER MICHIGAN. AM EXPECTING THIS TO
BURN OFF (NOT LIKE YESTERDAY) BY MID MORNING...BEFORE ONE VORTICITY
MAXIMA NEAR MSP...SPREADS MID AND UPPER LEVEL CLOUDS INTO OUR NECK
OF THE WOODS. THIS PARTICULAR WAVE WILL LIFT THE DEEPER MOISTURE
FROM OUT WEST...UP AND OVER A DEVELOPING AND WEAK WARM FRONT. SKIES
ARE EXPECTED TO RETURN TO MORE CLOUDY...AND ALSO MAYBE PROVIDE SOME
LIGHT RAIN/SPRINKLES. THIS ADDED CLOUD...AND AN EXPECTED DECENT
LAYER OF FLAT CUMULUS (STUCK UNDER THE INVERSION) WILL LEAD TO A
RATHER TOUGH HIGH TEMPERATURE FORECAST. COULD ENVISION TEMPS
STRUGGLING TO REACH 70F IN MANY SPOTS...BUT THERE SEEMS TO BE ENOUGH
TIME DURING THE DAY FOR THE AUGUST SUN TO POP OUT AND GET MOST
EVERYONE INTO THE LOWER HALF OF THE 70S. SKIES WILL JUST THICKEN IN
CLOUDS HEADING THROUGH THE NIGHT...AS THE MAIN TROUGH NEARS...AND
MORE AND MORE MOISTURE IS FORCED INTO NRN MICHIGAN. DEEP LAYER
FORCING INCREASES AND THERE WILL BE POCKETS/AREAS OF SHOWERS AND
MAYBE A STORM OR TWO (ALTHOUGH INSTABILITY WILL BE SMALL/MINIMAL).
THESE WILL PRIMARILY BE ACROSS NW LOWER AND EASTERN UPPER. LOWS IN
THE UPPER HALF OF THE 50S.

.LONG TERM...(TUESDAY THROUGH SUNDAY)
ISSUED AT 352 AM EDT MON AUG 18 2014

...LOCALLY HEAVY MIDWEEK RAINFALL POSSIBLE...

HIGH IMPACT WEATHER POTENTIAL: LOCALIZED HEAVY RAIN POSSIBLE WITH
SLOW MOVING SHOWERS AND EMBEDDED STORMS TUESDAY AND WEDNESDAY.

PATTERN SUMMARY: A BIT OF A DIFFERENT LOOK TO THE FLOW REGIME FOR A
CHANGE THIS SUMMER...FEATURING BUILDING HEIGHTS INTO THE GULF OF
ALASKA WITH TIME THROUGH MIDWEEK...FAVORING THE STRENGTHENING OF
DOWNSTREAM TROUGHING THROUGH THE WESTERN STATES. THAT IN TURN WILL
LEAD TO OVERALL RISING HEIGHTS OVER THE EASTERN CONUS...BUT AS HAS
BEEN THE CASE SO MUCH THIS YEAR...THERE`S ALWAYS A WRINKLE OR TWO IN
AN OTHERWISE STRAIGHT-FORWARD FORECAST. THIS TIME THAT FEATURE IS A
SLOW MOVING UPPER WAVE CURRENTLY SITUATED OVER THE NORTHERN PLAINS/
SOUTHERN MANITOBA...SLATED TO SLOWLY MEANDER EASTWARD AND WORK
THROUGH THE BURGEONING UPPER RIDGE ACROSS THE GREAT LAKES INTO
WEDNESDAY. THEREAFTER...THERE ARE CONTINUED SIGNS THAT UPPER RIDGING
WILL BRIEFLY AMPLIFY OVERHEAD TOWARD LATE WEEK AND NEXT WEEKEND...
ALL AHEAD OF THE EASTWARD-EMERGING WESTERN TROUGH.

A LOOK AT THE DETAILS...

TUESDAY-WEDNESDAY: BY FAR THE PERIOD OF MOST INTEREST AS A VERY SLOW
MOVING UPPER LOW MEANDERS OVERHEAD. QUITE THE INTERESTING SETUP FROM
A SNEAKY HEAVY RAIN PERSPECTIVE...WITH AN AXIS OF ENHANCED MOISTURE
(PWATS UP AROUND 1.75 INCHES) WRAPPING NORTHWARD INTO THE REGION.
THIS SYSTEM HAS A RECENT HISTORY OF BEING ONE THAT HAS PRODUCED SOME
TREMENDOUS RAINFALL TOTALS ACROSS MONTANA/NORTH DAKOTA...WITH EVEN A
FEW SPOTS OVER THE PAST 48 HOURS PICKING UP IN EXCESS OF 8 INCHES OF
RAIN (YIKES!). FORECAST RAOBS CONTINUE TO EXHIBIT A TROPICAL LOOK...
FEATURING DEEP/SKINNY CAPE PROFILES OF UP TO 1000 J/KG COMBINED WITH
VERY HIGH FREEZING LEVELS UP AROUND 13KFT IN THE PRESENCE OF WEAK
STEERING FLOW ONLY AROUND 10 KNOTS THROUGH THE PERIOD. WEAK BUT
PERSISTENT DEEP LAYER WARM ADVECTION SHOULD PROVIDE THE BACKGROUND
ASCENT TO DRIVE THE SYNOPTIC COMPONENT TO RAINS...WITH SAID SKINNY
INSTABILITY AIDING IN CONVECTIVE ENHANCEMENT...PARTICULARLY BOTH
TUESDAY AND WEDNESDAY AFTERNOONS.

BASED ON THE SETUP...WOULDN`T AT ALL BE SHOCKED TO SEE SOME SPOTS
PICK UP IN EXCESS OF 2 INCHES OF RAIN THROUGH THE MIDWEEK PERIOD...
PERHAPS SIGNIFICANTLY HIGHER IN SPOTS SHOULD ANY CONVECTIVE ELEMENTS
TRAIN OVER THE SAME AREAS. THE BEST POTENTIAL FOR HEAVY RAINS LOOKS
TO COME ACROSS NORTHERN LOWER WHERE THE COMBINATION OF MOIST INFLOW
AND LOW/MID LEVEL WARM ADVECTION ASCENT WILL OVERLAP. OVERALL...SAID
EXPECTED RAINS SHOULD HAVE ANY MAJOR EFFECT ON RIVERS GIVEN THE TIME
OF YEAR AND NOT-SO-SATURATED SOILS...WITH THE EXCEPTION OF NORTHEAST
LOWER WHERE LAST WEEK`S HEAVY RAINS PRODUCED UP TO 4-5 INCHES IN
SPOTS. THAT AREA WILL HAVE TO BE MONITORED CLOSELY.

WEDNESDAY NIGHT-FRIDAY: LOW CONFIDENCE PORTION OF THE FORECAST WITH
REGARD TO THE EVOLUTION OF PRECIPITATION. OUR MIDWEEK UPPER LOW WILL
BE WORKING EAST INTO NEW ENGLAND...LEAVING RISING HEIGHTS OVER THE
WESTERN LAKES THROUGH THE DAY ON FRIDAY. RECYCLING OF LOWER LEVEL
DRY AIR AROUND THE PERIPHERY OF QUEBEC RIDGING MAY JUST TRY TO PUT
THE KIBOSH OF ANY BIG PRECIP THREAT UP THIS WAY...AS THE FOCUS FOR
ONE OR MORE CONVECTIVE COMPLEXES SITS JUST OFF TO OUR SOUTH AND
WEST. AT THE MOMENT...THAT AREA LOOKS TO RESIDE ON THE NORTHERN
PERIPHERY OF STRONG LOW LEVEL THERMAL RIDGING ON THE SOUTHERN FLANK
OF BETTER UPPER JET SUPPORT. OFTEN THAT WILL BE WHERE THE MCS TRACK
LIES AND BASED ON CLIMO IN SUCH SETUPS...HAVE LITTLE REASON TO ARGUE
THAT MOST OF THE ACTIVITY WILL SIT JUST OFF TO OUR SOUTH. WITH THAT
SAID...OF COURSE ANY SUBTLE SHIFT IN THE RIDGE PLACEMENT WILL HAVE A
BIG IMPACT ON OUR PRECIP POTENTIAL...BUT REALLY HATE TO CLUTTER UP
THE FORECAST WITH SUCH LOW CHANCE POPS WHEN THE GREATER LIKELIHOOD
WILL BE REMOVED FROM OUR CWA.

FRIDAY NIGHT-SUNDAY: MORE LOWER CONFIDENCE FORECASTING INTO THE
WEEKEND WITH NOTABLE DISCREPANCIES AMONG THE GUIDANCE REGARDING THE
SHARPNESS OF THERMAL RIDGING THAT WILL BUILD THIS FAR NORTH. THE
OPERATIONAL ECMWF AND GFS ENSEMBLE MEAN CONTINUE TO ADVERTISE A MUCH
MORE SUPPRESSED SETUP...OFFERING BETTER CONVECTIVE CHANCES WELL OFF
TO THE SOUTH THROUGH THE TENNESSEE/OHIO VALLEYS. MEANWHILE THE GFS
IS OUT ON ITS OWN WITH A MORE AMPED NORTHERN STREAM WAVE HELPING
SIGNIFICANTLY BUILD UPPER RIDGING INTO THE GREAT LAKES. BASED ON
HISTORY THIS YEAR...WOULD HAVE TO LEAN TOWARD THE ECMWF AT THIS
JUNCTURE...BUT A BLENDED APPROACH SHOULD WORK THAT FAR OUT...WITH
ONLY SMALL RAIN CHANCES BUT TEMPS APPROACHING OR EVEN BRIEFLY
EXCEEDING LATE AUGUST NORMALS.

&&

.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z TUESDAY MORNING)
ISSUED AT 655 AM EDT MON AUG 18 2014

...DENSE FOG AND STRATUS THIS MORNING WITH RAIN CHANCES INCREASING
THROUGH TONIGHT...

RELATIVELY MOIST LOW LEVEL AIR WITH WEAK WINDS AND DRY UPPER LEVELS
HAS RESULTED IN THE FORMATION OF IFR/LIFR STRATUS AND FOG. THIS
MOISTURE WILL GET LIFTED UNDERNEATH A PRONOUNCED INVERSION...WHICH
WILL RESULT IN AN EVENTUAL FLAT CUMULUS FIELD. MID AND UPPER LEVEL
MOISTURE WILL INCREASE AS WELL...DUE TO THE ADVANCEMENT OF WEAK LOW
PRESSURE FROM THE DAKOTAS/MN. CLOUDS WILL THICKEN INTO THE
NIGHT...WITH CIGS EXPECTED TO REMAIN JUST ABOVE MVFR...AND SHOWERS
OVER THE NW LOWER AIRPORTS.

WINDS WILL BE LIGHT...UNDER 10 KTS...TRENDING ONSHORE TODAY...BUT
THE LARGER SCALE FLOW WILL BE OUT OF THE SE.

&&

.MARINE...
ISSUED AT 352 AM EDT MON AUG 18 2014

OVERALL...WEAK SFC LOW PRESSURE WILL SLOWLY WORK IN OVER THE
GREAT LAKES THROUGH TUESDAY-WEDNESDAY BRINGING PERIODS OF SHOWERS
AND SOME THUNDERSTORMS. THE PRESSURE GRADIENT WILL BE LOOSE...WITH
WINDS REMAINING UNDER ADVISORY LEVELS FOR MOST ALL NEARSHORES OVER
THE NEXT SEVERAL DAYS.

THE PRESSURE GRADIENT DOES TIGHTEN TUESDAY AND TUESDAY NIGHT
ACROSS THE STRAITS/FAR NRN LAKE HURON AND WHITEFISH BAY. HERE IS
WHERE WINDS MAY APPROACH ADVISORY LEVELS.


&&

.APX WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LH...NONE.
LM...NONE.
LS...NONE.

&&

$$

SYNOPSIS...LAWRENCE
SHORT TERM...SMD
LONG TERM...LAWRENCE
AVIATION...SMD
MARINE...SMD






USA.gov is the U.S. government's official web portal to all federal, state and local government web resources and services.